The present invention is directed to a molded product from recycled carpet waste. More particularly, the invention is directed to a process of producing a molded product from recycled carpet wherein the molded product includes carpet fibers dispersed in a polyvinyl chloride matrix.
Plastics are in common use in a large portion of consumer products. The increased use of plastics is, to a large extent, due to the low cost of plastics in comparison to other materials. In addition, plastics provide durability and strength that are not available from other materials. An inherent property of most plastic materials is that they are not readily biodegradable. This creates a large volume of waste in landfills.
In recent years, there has been increased awareness of the disposal difficulties of plastics and an increased effort to recycle plastic materials. Many plastics are very difficult to recycle into usable materials. Although most thermoplastics can be remelted, the properties of the resulting blend of polymers are difficult to control. The processing properties of most recycled plastics are sufficiently different from the virgin plastic that extruding and molding the recycled plastic is very difficult. In addition, contamination from incompatible plastics and other foreign materials produce inconsistent properties throughout the plastic and a poor quality product. Moreover, contamination can clog conventional plastics processing equipment, thereby making recovery of these materials unpractical.
Recycling of plastics at this time is limited primarily to packaging materials, such as plastic bottles and containers. The recycling of polyethylene terephthalate (PET) has been successful in part due to comparative ease of reclamation and volume of available high quality materials. Other materials which have experienced some success in recycling include high density polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyacrylates, polycarbonates and polyurethanes.
A primary difficulty in recycling many products is the number of different plastics and the varying amounts of plastics in the product. Various processes have been proposed to separate the plastic materials according to type. However, these processes are difficult to control and are typically expensive. In addition, it can be difficult to identify some types of plastics by visual inspection.
Carpeting is one example of a product that usually includes a combination of different polymeric materials. In particular, the carpet fibers are generally different from the materials used for backing. Separating waste carpeting into the respective components is very difficult and generally not economically feasible. Post consumer carpets usually contain large amounts of dirt and other foreign materials which increase the difficulty of recycling. Each year, large volumes of waste carpet are discarded as industrial scrap in the form of trimmings during manufacture or installation as well as post consumer carpet. Regardless of the source, most carpet materials are difficult to recycle.
There has been some effort to recycle various materials that contain filaments or fibers. Examples of processes which use recycled materials are disclosed in U.S. Pat. No. 5,560,797 to Burt et al and U.S. Pat. No. 5,719,198 to Young et al.
Accordingly, there is a continuing need in the industry for processes of recycling various plastic materials and particularly carpeting.
The present invention relates to a product and to a process of producing a molded plastic product containing at least a portion of scrap or waste plastic materials. In particular, the present invention is directed to a process of producing a molded plastic product from carpet scrap.
Accordingly, a primary object of the invention is to provide a product and a process for producing a molded product using polyvinyl chloride-backed carpet scrap.
Another object of the invention is to provide a product and a process for producing a molded product containing recycled carpet scrap having a fiber component and a polyvinyl chloride component and additional polyvinyl chloride in an amount sufficient to form a polyvinyl chloride matrix having carpet fibers dispersed therein.
A further object of the invention is to provide a molded product containing recycled carpet scrap that is flexible and wear-resistant.
Still another object of the invention is to provide a flexible floor tile comprising about 10 to about 75% by weight of recycled carpet scrap where the floor tile contains the recycled carpet fibers uniformly dispersed therein.
Another object of the invention is to provide an economical process for recycling vinyl-backed carpet scrap into a durable product.
A further object of the invention is to provide a process for utilizing carpet scrap substantially without reducing the length of the carpet fibers.
Still another object of the invention is to provide a process of producing a molded matrix of polyvinyl chloride having recycled carpet fibers substantially uniformly dispersed therein.
These and other objects of the invention are attained by providing a product having a fiber-reinforced, flexible matrix, wherein said matrix comprises about 10% to about 75% by weight of waste scrap carpeting, said carpeting having a polyvinyl chloride backing and carpet fibers from a polymer having a melting point higher than the melting point of polyvinyl chloride, and about 25% to about 90% by weight of flexible polyvinyl chloride. The product can also contain up to about 5% by weight of a polyvinyl chloride plasticizer, and up to about 5% of a polyethylene copolymer. The matrix is a substantially continuous phase of polyvinyl chloride and carpet fibers dispersed therein.
The objects and advantages of the invention are further attained by providing a process for forming a molded article comprising the steps of supplying a feed mixture to the inlet of an extruder, said feed mixture comprising carpet scrap having a fiber component and a polyvinyl chloride component, and a source of flexible polyvinyl chloride, heating said feed mixture in said extruder to a temperature sufficient to melt said polyvinyl chloride of said carpet scrap and of said polyvinyl chloride source without melting said fiber component and substantially without reducing the fiber length to form a substantially uniform mixture of melted polyvinyl chloride and an unmelted fiber component, discharging said mixture from said extruder and shaping and cooling said mixture to form a molded article of a matrix of polyvinyl chloride having said unmelted fiber component dispersed therein.
These and other objects, advantages and salient features of the invention will become apparent from the drawings and detailed description of the invention.